The processing of contaminate laden fluid such as oily wastewater collected within marine vessels, by passage through ultra-filtration membranes for fluid cleansing purposes is generally known in the art, involving a module containing one or more of such filtration membranes having pores through which the oily wastewater percolates during passage through a tubular module housing. Various problems arise with respect to providing a suitable arrangement of apparatus for the performance of such wastewater cleansing operation in such installationson board marine vessels, imposing different handling requirements and dimensional restrictions. It is therefore an important object of the present invention to provide a more efficient and less costly arrangement of bundled elements such as filter membranes within modules for cleansing of contaminate laden fluids such as oily wastewater by filtration through the filter membranes.